Fertilization occurs about the beginning of week 3 of pregnancy. This happens when one of the sperm penetrates the egg and the membranes of the sperm and egg unite thus indicating pregnancy. At that point, it is impossible for other sperm to enter. The fertilized egg of a divides until a solid ball of cells is formed.
Next, it travels down the fallopian tube into the uterus, during a seven to ten day trip, where it eventually implants into the uterine lining and continues to grow and develop. You are now pregnant.
You're not even aware that you've conceived, yet, since you haven't even missed a period, although you might have noticed when you ovulated. At the end of this week, you may get the first of your pregnancy symptoms. You might experience some spotting or light bleeding at the time of implantation.
